Title: H_∞ controller for stability enhancement in VSC HVDC system with parallel AC lines

Authors: P.K. Dash, A.K. Moharana

Addresses: Postgraduate Studies and Research, Silicon Institute of Technology, Bhubaneswar-751024, India. ' Department of Electrical and Computer Engineering, University of Western Ontario, London-N6G 5E5, Canada

Abstract: In this paper, a state-space model for a voltage source converter based high voltage direct current (VSC HVDC) transmission link in parallel with an AC transmission line is developed using dq-coordinate system. A robust H_∞ control design for the converter and inverter of the VSC HVDC system is proposed to maintain the DC voltage and control the active and reactive power at the converter stations. The H_∞ control for the converter control systems is realised using output feedback control obtained by measuring the converter side DC voltage and reactive power, and the inverter side active and reactive power and satisfying the H_∞ norm of the closed loop transfer function matrix. Simulation results with a large number of disturbances like torque changes and three-phase short circuits at the converter and inverter buses demonstrate the effectiveness of the designed controller and robustness with respect to the variations of the system operating conditions.

Keywords: voltage source converters; high voltage direct current; VSC HVDC; parallel AC lines; H-infinity control; robust control; feedback control; state-space modelling; AC transmission lines; converter control; simulation.

DOI: 10.1504/IJPEC.2009.027945

International Journal of Power and Energy Conversion, 2009 Vol.1 No.2/3, pp.215 - 242

Published online: 20 Aug 2009 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article